Quantitative measure of the rotational inertia of a body. As a rotating body spins about an external or internal axis (either fixed or unfixed), it opposes any change in the body's speed of rotation that may be caused by a torque. It is defined as the sum of the products obtained by multiplying the mass of each particle of matter in a given body by the square of its distance from the axis of rotation
The moment of inertia of a body about an axis perpendicular to plane of its surface is called polar moment of inertia Hence, polar moment of inertia is a mass distribution property about an axis perpendicular to its surface
The resistance of an object to rotational acceleration When the mass of an object is distributed far from its axis of rotation, the object is said to have a high polar moment of inertia When the mass distribution is close to the axis of rotation, it has a low polar moment of inertia A mid-engined car has most of its mass within its wheelbase, contributing to a low polar moment of inertia, which, in turn, improves cornering turn-in
Is the sum of any two moments of inertia about axes at right angles to each other It is taken about an axis which is perpendicular to the plane of the other two axes